It is known to construct an electrosurgical instrument in the form of a handpiece, a tubular shaft mounted in the handpiece and, at a distal end of the shaft, at least one fixed or movable electrode supplied with a radio frequency electrical potential via a conductor passing through the shaft and the handpiece. In an instrument for laparoscopic use in particular, it is advantageous to be able to rotate the electrode or electrodes about the axis of the shaft with respect to the handpiece. In addition, it is conventional to be able to remove and replace electrodes so that new electrodes are used for each surgical procedure. Generally, the remainder of the instrument is sterilisable and can be used for a number (typically 10) of operations before disposal.